/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.1
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
	This file is part of foam-extend.

	foam-extend is free software: you can redistribute it and/or modify it
	under the terms of the GNU General Public License as published by the
	Free Software Foundation, either version 3 of the License, or (at your
	option) any later version.

	foam-extend is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.

\*---------------------------------------------------------------------------*/

#include "IOobject.H"
#include "dictionary.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

bool Foam::IOobject::readHeader(Istream& is)
{
	if (IOobject::debug)
	{
		Info<< "IOobject::readHeader(Istream&) : reading header for file "
			<< is.name() << endl;
	}

	// Check Istream not already bad
	if (!is.good())
	{
		if (rOpt_ == MUST_READ || rOpt_ == MUST_READ_IF_MODIFIED)
		{
			FatalIOErrorIn("IOobject::readHeader(Istream&)", is)
				<< " stream not open for reading essential object from file "
				<< is.name()
				<< exit(FatalIOError);
		}

		if (IOobject::debug)
		{
			SeriousIOErrorIn("IOobject::readHeader(Istream&)", is)
				<< " stream not open for reading from file "
				<< is.name() << endl;
		}

		return false;
	}

	token firstToken(is);

	if
	(
		is.good()
	 && firstToken.isWord()
	 && firstToken.wordToken() == "FoamFile"
	)
	{
		dictionary headerDict(is);

		is.version(headerDict.lookup("version"));
		is.format(headerDict.lookup("format"));
		headerClassName_ = word(headerDict.lookup("class"));

		const word headerObject(headerDict.lookup("object"));
		if (IOobject::debug && headerObject != name())
		{
			IOWarningIn("IOobject::readHeader(Istream&)", is)
				<< " object renamed from "
				<< name() << " to " << headerObject
				<< " for file " << is.name() << endl;
		}

		// The note entry is optional
		headerDict.readIfPresent("note", note_);
	}
	else
	{
		SeriousIOErrorIn("IOobject::readHeader(Istream&)", is)
			<< "First token could not be read or is not the keyword 'FoamFile'"
			<< nl << nl << "Check header is of the form:" << nl << endl;

		writeHeader(Info);

		return false;
	}

	// Check stream is still OK
	if (is.good())
	{
		objState_ = GOOD;
	}
	else
	{
		if (rOpt_ == MUST_READ || rOpt_ == MUST_READ_IF_MODIFIED)
		{
			FatalIOErrorIn("IOobject::readHeader(Istream&)", is)
				<< " stream failure while reading header"
				<< " on line " << is.lineNumber()
				<< " of file " << is.name()
				<< " for essential object" << name()
				<< exit(FatalIOError);
		}

		if (IOobject::debug)
		{
			Info<< "IOobject::readHeader(Istream&) :"
				<< " stream failure while reading header"
				<< " on line " << is.lineNumber()
				<< " of file " << is.name() << endl;
		}

		objState_ = BAD;

		return false;
	}

	if (IOobject::debug)
	{
		Info<< " .... read" << endl;
	}

	return true;
}


// ************************************************************************* //
